Western Mountaineering Bag Expander

First I've heard of this.

My initial thought was that it could be used to make my WM bag big enough to insert another bag inside without compression, for winter camping.

…and it could add just enough space to fit clothing, boots etc.

It's not novel to WM as a few other companies do it as well if I'm not mistaken. WM must have had it as an option but no longer offers it.

I'd grab it in a heartbeat if it really works.

I am really considering this. Thanks for pointing it out.

I had been wanting to use my Summerlite with another summer bag I have, but they are both fairly tight fitting and compress too much when I put one inside the other.
This is especially true when I wear a down puffy jacket.

I would call or email Western Mountaineering about model and sizing questions.

I can see it working with all their bags because they probably use the same zipper on all models and sizes.
I can't say that is true with all sizes, but I suspect they make the length differences in the area below the zipper.

OK, I ordered one.

I figured it saves me money by allowing me more layering options instead of buying a real winter quilt/bag.

@ Steven. Would you please post your thoughts after you use the expander.

@Michael,

Will do.

I want one for my Megalite for winer use!

Looks like there are two models to choose from, either the "Summer" or the "Three Season". Guessing the fill amount is different and perhaps the amount of expansion?

EDIT: You can buy the "Summer" (I think) version for 25% off using the code "25OFF1" here:
http://www.backwoods.com/western-mountaineering-bag-expander-s

I just received the "S" version.
It has a tag that says that it will fit the sizes 5'6", 6', 6'6" and 7' versions of WM bags.

It appears to have approx. 3 inches of loft. Much thicker than my Summerlite.
Probably a perfect match for bags in the approximately 10 to 20 degree range and would probably even work well with warmer bags.

It is all black.

It weighs 5.4 ounces with the tags

It is 6" wide from zipper to zipper in the shoulder area, the inside fabric is approximately 8" wide on the internal side of the zipper. Wider on the inside so it overlaps the zippers to block drafts I would assume.

It gradually narrows down to 0" at the foot end of the zippers.

So it increases the internal circumference of the bag by 6" at the shoulders and 0" in the foot area.

Perfect for my needs. I can now layer bags and or wear more puffy layers inside without much compression.

Has had an expander available for its bags for a while now, FYI.

Big Agnes has had this option for quite some time as well.

I just ordered the three-season version and we'll see if it fits on my two WM bags. I'll report back and let you know whether it was a waste of money or money well spent.

Old thread rebirth… Did any of you have thoughts after ~ 7 years of using these expanders?  Do they work well with the 5’6 bags?  I know they are optimized for 6 footers but how do you think they would work for the shorter bags… or longer for that matter.

Thanks!

So glad this was resurrected…I didn’t know about these. My shoulders are too big for my Summerlite and this might do the trick…

One nice thing about getting our winter parkas from a local maker in Homer (80 miles down the road, NomarAlaska.com) was when my wife was pregnant, they made an “expander” to the jacket with the appropriate zippers on each side to match up to the original parka.

And I ordered mine dog musher style with a big pouch across the lower back with zippered access on each side, so I can reach back there and grab your bigger gloves, face mask or hat.

Just ran across this.  The expanders are current they are listed on price list just not featured on WM’s website. The biggest difference between “Summer” and “3 Season” is fabric. The Summer one is xTremelite; the 3 Season is xpMicrofiber. There is a slight .4 oz difference in fill. They do zip and mate perfectly to the 6 foot bags but will work with anything. I imagine there would be some overlap on the 5’6″ bags.  My favorite bags to use these with are my Caribou and my Sycamore. With the Caribou it helps cover the zipper since there isn’t a draft collar on that model; with the Sycamore it helps me feel less crammed in and able to utilize the hood more easily since the Sycamore (mine anyway) is sort of a 6′ “plus” bag meaning the bag is six feet and change with the hood (for the 6 foot version) and the hood is shorter than in most other models (hence the “with a hood just in case”).